Travel grant to support measurement of the astrophysical 4He(3He,g)7Be rate

支持天体物理 4He(3He,g)7Be 速率测量的旅费补助

• 批准号: ST/G006539/1
• 负责人: Brian Fulton
• 金额: $ 0.78万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FG006539%2F1
• 关键词: Travel; grant; support; measurement; astrophysical

The energy from our Sun, which is essential to maintain life here on Earth, results from a sequence of nuclear reactions which turn Hydrogen into Helium, releasing nuclear binding energy. Several of these reactions also result in the production of neutrinos, very weakly interacting particles which can escape from the Sun and reach us here on Earth. The measurement of these neutrinos in Earth based detectors has resulted in a paradigm shift, since it has revealed that neutrinos have a mass (previously we thought they were massless). The experimental effort is now directed at accurate measurements of the energy spectrum of the neutrinos, from which important details about the structure of neutrinos can be determined. However, paradoxically it is not the accuracy of the measurements which is the limit, but the uncertainty on the flux of neutrinos generated in the Sun. This uncertainty arises because we cannot model the nuclear reaction sequence properly because of uncertainties in the reaction cross sections. One of the key reactions is the fusion of a 3He and a 4He nucleus to form 7Be and the uncertainty in this reaction rate is the remaining major uncertainty in determining the high energy neutrino flux. The situation has been further confused by measurement reported earlier this year which shows a higher reaction rate than previously believed. Our experiment is designed to resolve this discrepancy and to reduce the experimental uncertainty in the cross section measurement.

太阳的能量对维持地球上的生命至关重要，它来自于一系列的核反应，这些反应将氢转化为氦，释放出核结合能。其中一些反应还会产生中微子，这种相互作用非常弱的粒子可以从太阳逃逸到地球上。基于地球的探测器对这些中微子的测量导致了范式的转变，因为它揭示了中微子有质量（以前我们认为它们是无质量的）。现在，实验工作的方向是精确测量中微子的能谱，从中可以确定有关中微子结构的重要细节。然而，矛盾的是，它不是测量的准确性是极限，而是在太阳中产生的中微子通量的不确定性。由于反应截面的不确定性，我们不能正确地模拟核反应序列，从而产生了这种不确定性。其中一个关键反应是3He和4He核融合形成7Be，这个反应速率的不确定性是确定高能中微子通量的主要不确定性。今年早些时候报告的测量结果显示，反应速度比之前认为的要高，这使情况更加混乱。我们的实验旨在解决这一差异，并减少实验不确定度在截面测量。